A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by another wire of 1 mm diameter carrying same current. The strength of magnetic field far away is
twice the earlier value
same as the earlier value
one – half of the earlier value
one quarter of the earlier value
when a charged particle moving with velocity is subjected to a magnetic field of introduction , the force on it is non – zero. This implies that
Angle between is necessarily 90o
Angle between can have any value other than 90o
Angle between can have any value other than zero and 180o
Angle between is either zero or 180o
The magnetic field at a distance r from a long wire carrying current I is 0.4 T. The magnetic field at a distance 2r is
0.2 T
0.8 T
0.1 T
1.6 T
A charged particle of charge q and mass m enters perpendicularly in a magnetic field Kinetic energy of the particle is E, then frequency of rotation
qB/m π
qB/2 πm
qBE/2 πm
qB/2 πE
The total charge induced in a conducting loop when it is moved in magnetic field depends on
the rate of change of magnetic flux
initial magnetic flux only
the total change in magnetic flux
final magnetic flux only
At what distance from a long straight wire carrying a current of 12 A will the magnetic field be equal to 3 x 10-5 Wb/m2?
8 × 10-2 m
12 × 10-2 m
18 × 10-2 m
24 × 10-2 m
None of the above
It may undeflected also
A beam of electrons is moving with constant velocity in a region having simultaneous perpendicular electric and magnetic fields of strength 20 Vm-1 and 0.5T, respectively at right angles to the direction of motion. Then the velocity of electrons must be :
8 m/s
20 m/s
40 m/s
1/40 ms
A coil of one turn is made of a wire of certain length and then from the same length a coil of two turns is made. If the same current is passed is both the cases, then the ratio of the magnetic induction at their centers will be
2 : 1
1 : 4
4 : 1
1 : 2
